[IMP] mass_mailing : opt-out filter by default in selection of recipient

To avoid spamming people who asked not to be spammed.

addons/crm/crm_lead_view.xml

@@ -374,7 +374,7 @@
                     <separator />
                     <filter string="New Mail" name="message_unread" domain="[('message_unread','=',True)]"/>
                     <separator />
-                    <filter string="Available for mass mailing"
+                    <filter string="Exclude Opt Out"
                             name='not_opt_out' domain="[('opt_out', '=', False)]"
                             help="Leads that did not ask not to be included in mass mailing campaigns"/>
                     <group expand="0" string="Group By">

addons/mass_mailing/views/mass_mailing.xml

@@ -396,7 +396,8 @@
 
                                 <field name="mailing_domain" widget="char_domain"
                                     placeholder="Select recipients"
-                                    options="{'model_field': 'mailing_model', 'model_domain': 'mailing_domain'}"/>
+                                    options="{'model_field': 'mailing_model', 'model_domain': 'mailing_domain'}"
+                                    context="{'search_default_not_opt_out':1}"/>
 
                                 <div attrs="{'invisible': [('mailing_model', '&lt;&gt;', 'mail.mass_mailing.contact')]}">
                                     <label for="contact_list_ids" string="Select mailing lists:" class="oe_edit_only"/>